Ch. 6 Quiz Review
An air parcel will cool at the dry adiabatic lapse if it is lifted, remains unsaturated, and does not exchange energy or mass with its environment during lifting.
True
Clouds tend to form on the windward sides of mountains because the mountains act as a lifting mechanism.
True
Convection is more likely to develop by mid-afternoon on a summer day when the morning skies are clear rather than on a day when morning skies are overcast.
True
The base of a cloud is the altitude where the lifting condensation level is located.
True
When air parcel reaches the lifting condensation level it will ____ and when it reaches the level of free convection it will ____.
b. form a cloud; become buoyant
Air can become unstable by which of the following?
being lifted to its level of free convection by an advancing cold front being heated during the day by solar radiation
How can the atmosphere's stability at a particular location be changed?
change the vertical temperature structure
Air above the tropopause ____:
is absolutely stable
If a parcel of air is displaced vertically in a(n) ___ environment, it will ___.
stable; return to its original position.
A conditionally unstable atmosphere is ___ for an air parcel that is unsaturated and ___ for an air parcel that is saturated.
stable; unstable
Air will rise at the moist adiabatic laps rate if its relative humidity is between 50 and 75%
False
An air parcel is stable if its temperature exceeds the temperature of its surrounding environment.
False
An air parcel is stable if, for a small displacement, it accelerates away from its original position.
False
From rawinsonde data alone, it is not possible to evaluate the environmental lapse rate.
False
The dry adiabatic lapse rate is about 6*C/km near the surface, but larger in the middle and upper troposphere.
False
Which of the following Lifted Index values would best characterize an atmosphere with the potential to produce severe thunderstorms and possibly tornadoes?
LI = -4
In the atmosphere, a parcel of air is ___ than its environment if the parcel is ___ the environment.
less dense; warmer than
A lifted air parcel first becomes unstable when it reaches what point in the atmosphere?
level of free convection
The base of a thunderstorm cloud is found at the ____.
lifting condensation level
If an air parcel is lifted, it will first form clouds at the ____ and become buoyant (unstable) at the ____.
lifting condensation level; level of free convection
In terms of diurnal changes in stability, the atmosphere is typically most stable during ___ and least stable during ____.
night; day
If an air parcel is displaced vertically in a stable environment, what will the parcel do?
return to its original position
If an air parcel is ____, it will ____ at the most adiabatic lapse rate.
saturated; expand and cool
If you wanted to evaluate the stability of the atmosphere, which weather product would you examine?
sounding
Positive values of the Lifted Index favor thunderstorms, while negative values favor stable conditions and the absence of convective clouds.
False
As an air parcel rises what happens to its size and temperature?
It expands and cools
What will happen if a parcel of air is displaced vertically in an unstable environment?
It will continue to accelerate away from its original position.
Why is understanding stability important in the study of severe storms?
Stability determines the location and intensity of convective storms in the atmosphere.
Most thunderstorms do not extend very far into the stratosphere. What is the reason for this?
The stratosphere is stable since the stratosphere is an inversion layer and therefore inhibits vertical motions.
Air lifted through a lifting condensation level will not necessarily become buoyant. The air must be lifted through its level of free convection before it will rise freely.
True
In the atmosphere, a rising air parcel will expand.
True
The Lifted Index is a tool used by meteorologists to estimate atmospheric stability.
True
The environmental lapse rate varies in time and place, but the dry adiabatic lapse rate does not.
True
The most adiabatic lapse rate normally has a smaller value than the dry adiabatic lapse rate.
True
When air parcel reaches the lifting condensation level it will ____ and when it reaches the level of free convection it will ___.
a. change lapse rates from the dry adiabatic lapse rate to the moist adiabatic lapse rate; continue to cool at the moist adiabatic lapse rate
What information on a sounding allows you to calculate the environmental lapse rate?
air temperature
